Vaccines

Question 1

What is a vaccine?

Answer 1

Contains dead pathogen which stimulates the production of antibodies

Question 2

Vaccines protect people against disease. Explain how. (5)

Answer 2

Vaccines contain dead pathogens
Memory cells made
On second exposure memory cells produce antibodies
Rapidly produces antibodies
Antibodies destroy pathogens

Question 3

What is herd immunity?

Answer 3

‘If enough people are vaccinated
against a disease, it is not possible for
a disease to spread through a
population’

Question 4

What is antigenic variability?

Answer 4

• Some pathogens change their surface antigens.
• Formed due to changes in genes (mutations) within the pathogen
• Memory cells don’t recognise the different antigens –
new primary response

Question 5

What is active immunity?

Answer 5

• it requires exposure to an antigen
• the body makes it own antibodies
• develops slowly
• Long-term because memory cells enable
  faster antibody production on re-infection

Question 6

What is passive immunity?

Answer 6

• doesnt require exposure to antigen
• body given antibodies made by someone else
• immediate
• Short-term protection as antibodies are
  broken down and no memory cells are made